My stairs from the basement to main level were opened up, during a whole-house renovation 13 years ago .. before I bought the place. Visually, it opens up the foyer, but in the winter, I have no way to close off the cold air coming up from the basement .. something for you to think about. Why were you thinking about opening it up?

The house is not being lived in. We are going to update. I always wanted a pretty staircase

I would check with an architect or builder. Seeing the upstairs and the fact that you have a hallway that runs along what appears to be the upper portion of the wall it doesn't look like it could be removed and still have a passageway to the other upstairs rooms. Not sure what is on the other wall and if it needs to be retained structurally if you were thinking of widening it - but I'd get it checked out.

Tough call from here. Inevitably we are talking about moving bearing walls.....and I don't know if more than one is bearing. Definitely the long wall of the stairs on both sides. But potentially the wall between the living room and dining room. I think that will need to be removed to create a more open floor plan...and make the effort of exposing the stair visible from somewhere besides the dining room. Not knowing joist direction or foundation locations or roof directions...Can't tell if it is carrying load. But...I think if you are going to stay with the house for a longer period of time it may be worth the emotional investment and net at least that return on investment...most likely not going to see a giant dollar ROI for the staircase renovation. i actually think opening up this stair may help the HVAC system to balance...since it is going from conditioned space to conditioned space and the thermostat is probably on the main level.